Windows 7's Action Center does a great job of compressing all of Windows' update/alert/whatever notifications into one icon, but it takes some tweaking to make it show what you want, or disable it entirely.

At the How-To Geek's home away from Lifehacker, his partner in serious Windows customization, Mysticgeek, details the process of defining exactly which kind of system message get displayed through the Action Center's little white flag icon. It's all done through the Control Panel and right-click options, no registry hacking required, but the process might not be apparent to Windows 7 newcomers. And for those who don't want their system to bother them at all, there's a simple fix for disabling the Action Center for real. Hit the link for a walkthrough full of explanatory screenshots.